With options that use a dropdown list, any [+] or [-] button next to adds or removes items in the list itself

View HTML Source Code to Find and Solve Errors

Using A1 Sitemap Generator
you can quickly discover and report a wide range of errors, in particular website linking errors.
However, viewing the HTML page source is often needed to pintpoint and fix a specific error.

As shown in screenshot, the source editor supports HTML syntax highligting and shows line/column numbers.
You can have the editor perform syntax highlighting through the menu item Tools | Syntax highlight document.

If the viewed file resides on local file system, it is possible to save changes using
File | Update file.

You can use the
A1 Website Analyzer tool to
HTML validate your entire website during scan.